I have five living together in a tall ten gallon. No idea what sex, but I'm not sure they're big enough to tell yet. Since I rehoused them, I actually see them out quite a bit in the evening. They're fun to watch, especially when they run into each other and tap around furiously. Speedy hunters too.I thought something was odd about how they looked. Do you know if you have a male or female and do you have more than just the one ??